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BACKGROUND The effect of the addition of hydroxypropyl methylcellulose ( HPMC) on the textural properties of low-fat tofu was investigated. Three fat levels (240, 100 and 30 g kg−1) were used to make tofu, which were identified as C (full-fat tofu), L1 and L2. HPMC (5 g kg−1) was added to soymilk to prepare control and low-fat tofu, designated as CH, L1H and L2H. RESULTS Soymilk with a lower fat level had a lower viscosity: 143 (C), 100 ( L1) and 42 ( L2) cP. The addition of HPMC increased the viscosity of all types of soymilk, particularly in L2H (107 cP). With fat reduction, tofu syneresis increased from 19% (C) to 29% ( L2), although syneresis of L2H recovered to 19%, which is similar to high-fat control tofu. Decreased fat resulted in a lower firmness in L2 (0.67 N) compared to control (0.78 N). Firmness increased to 1.08 N in L2H tofu, whereas the firmness of CH tofu was 0.63 N. All types of tofu showed a denser, well-connected and cross-linking structure when HPMC was added, especially in L2H tofu. CONCLUSION HPMC improved the texture of the low-fat tofu by creating a harder texture and reducing syneresis. HPMC is an effective fat replacer for lower fat soymilk. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND Preventing post-harvest waste of Palmyra palm ( Borassus aethiopum Mart.) fruits is possible by recovery of pectin as a value-added ingredient. Extraction conditions on yield and functionality of Palmyra palm pectin was determined at different temperatures and pH values with 30 min extraction time. RESULTS Palmyra palm fruits contain more than 650 g kg−1 galacturonic acid and produce soft gels with sucrose in acidic media despite a high degree of acetylation (∼5%). Mechanical deformation of pectin gel was similar when extracted at pH 2.5 and 70 °C or under natural pH at room temperature or 70 °C. Pectins isolated at pH 7 exhibited comparable gel softness ( G′/ G″) with commercial pectin. Palm pectins also showed emulsifying activity greater than 50%, attributed to high protein content of 8 g 100 g−1. For pectins extracted at pH near 5.2-5.5, molar mass ranged from 3.00 to 3.38 × 105 g mol−1; intrinsic viscosity ranged from 218 to 297 mL g−1; arabinose was the main neutral sugar; ζ-potential ranged from −23 to −25 mV. CONCLUSION Palm fruit offers an inexpensive raw material to extract pectin in environmentally friendly and economical way and yield a pectin with unique gelling, viscosifying and emulsifying properties. © 2016 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND Tofu made from low-fat soy flour is a nutritional food for consumers and economically benefits the food processor. However, low-fat tofu has poor textural quality, especially insufficient firmness. Stepwise heating (heating at 75 °C, followed by holding at 95 °C) of full-fat soymilk increases gel properties. Therefore we evaluated the two-step heating of low-fat soymilk to improve tofu texture. RESULTS The denaturation enthalpy and temperature of β-conglycinin and glycinin were higher in low-fat tofu compared to high-fat tofu. The viscosity of low-fat soymilk and texture of tofu by one-step heating were weaker than full-fat soymilk and tofu. However, the two-step heating increased free sulfhydryl groups and viscosity of low-fat soymilk to a value higher or similar to conventional soymilk. The syneresis of low-fat tofu was reduced about 30% and hardness was higher (131.0 N) by the two-step process compared to one-step heating of full-fat tofu (101.4 N) by the one-step process. The microstructure of low-fat tofu became finer, denser and more homogeneous by the two-step heat process. CONCLUSION Low-fat tofu produced by denaturing the two major soy proteins separately had improved textural qualities similar to full-fat tofu as a result of increased hydrophobic interactions between denatured protein molecules. © 2014 Society of Chemical Industry [ABSTRACT FROM AUTHOR]